[PATCH 14/29] vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA

[Kees Cook]

Many architectures have an EXCEPTION_TABLE that needs only to be
read-only. As such, it should live in RO_DATA. This creates a macro to
identify this case for the architectures that can move EXCEPTION_TABLE
into RO_DATA.

Signed-off-by: Kees Cook <keescook at chromium.org>
---
 include/asm-generic/vmlinux.lds.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index d57a28786bb8..35a6cba39d9f 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -69,6 +69,17 @@
 #define NOTES_HEADERS_RESTORE
 #endif
 
+/*
+ * Some architectures have non-executable read-only exception tables.
+ * They can be added to the RO_DATA segment by specifying their desired
+ * alignment.
+ */
+#ifdef RO_DATA_EXCEPTION_TABLE_ALIGN
+#define RO_DATA_EXCEPTION_TABLE	EXCEPTION_TABLE(RO_DATA_EXCEPTION_TABLE_ALIGN)
+#else
+#define RO_DATA_EXCEPTION_TABLE
+#endif
+
 /* Align . to a 8 byte boundary equals to maximum function alignment. */
 #define ALIGN_FUNCTION()  . = ALIGN(8)
 
@@ -508,6 +519,7 @@
 		__stop___modver = .;					\
 	}								\
 									\
+	RO_DATA_EXCEPTION_TABLE						\
 	NOTES								\
 									\
 	. = ALIGN((align));						\
-- 
2.17.1